This invention is directed in general to the joining of a plurality of workpieces for assemblies wherein it is important to accurately position one workpiece with respect to another, and wherein problems arise due to a lack of proper radial support for one of the workpieces.
The preferred embodiment related to friction welding and more particularly to a method and apparatus for inertia welding spindle assemblies and other assemblies wherein a first workpiece is to be welded within or extending through at least one other workpiece such that the proper radial positioning of the first workpiece with respect to the at least one other workpiece is of importance.
Inertia type friction welding has been widely employed for joining many types of workpieces. In many cases, one workpiece is to be joined within or extending through a second workpiece, and due to the length of the first workpiece and/or the tolerances involved, obtaining proper radial positioning between the parts to be joined has posed a significant problem.
Conventionally, in inertia welding one workpiece is rotated with respect to a second workpiece, and once the proper speed is reached the rotational drive is disconnected via a clutch mechanism and one of the workpieces is upset into contact with the other to cause the workpieces to bond together. In prior art devices for practicing this type of inertia welding, the drive mechanism which rotated one of the workpieces also served to provide the workpiece with radial support. In certain instances, where elongated workpieces were to be bonded, a collet such as shown in U.S. Pat. No. 3,452,421 was utilized which enabled the workpiece to pass through the collet into the shaft of the drive member. In this manner, the amount of unsupported workpiece extending out of the chuck towards the other workpiece to which it was to be bonded could be held to a minimum. However, in inertia welding certain types of structures such as spindle assemblies for automotive vehicles, the elongated workpiece could not be grasped closely to its free end due to the configuration of the workpiece to which it is to be bonded, and also due to the fact that the elongated workpiece had to extend into and through the other workpiece so as to be bonded in the proper position. Therefore, inertia welding those types of assemblies posed a problem due to the fact that it was not possible to shorten up on the elongated workpiece, thereby producing corresponding problems with respect to dimensional accuracy and alignment of the workpieces after welding.
It is, therefore, a primary object of this invention to provide a method and apparatus for inertia welding assemblies which include an elongated workpiece and which obviate the above-noted problems with respect to dimensional accuracy and alignment of the workpieces.
The present invention solves these problems by supporting the rotating elongated workpiece both in the headstock which provides the rotational drive and in a separate radial support attached to or positioned on the opposite side of the tailstock, and since the elongated workpiece is supported at both ends, better dimensional accuracy and alignment can be achieved. Where the elongated workpiece passes through the member to which it is to be joined a sufficient distance to be grasped or held, the invention contemplates the use of various arrangements for providing the radial support such as collet chucking, tailstock supporting sleeves, or roller type steady rests. In those instances where the elongated workpiece does not extend completely through the workpiece, or where it does not extend sufficiently through the workpiece so as to be held within a supporting member, the invention contemplates providing the elongated workpiece with an extension member which can be fitted within the radial support member, or the use of a pin member extending from the radial support into engagement with the elongated workpiece.
These and other features, advantages and objects of this invention will become more apparent from the following detailed description and drawings in which: